Discovery of four gravitationally lensed quasars from the Sloan Digital Sky Survey

摘要

We present the discovery of four gravitationally lensed quasars selected from the spectroscopic quasar catalog of the Sloan Digital Sky Survey (SDSS). We describe imaging and spectroscopic follow-up observations that support the lensing interpretation of the following four quasars: SDSS J0832+ 0404 (image separation theta = 1.'' 98, source redshift z(s) = 1.115, lens redshift z(l) = 0.659); SDSS J1216+ 3529 (theta = 1.'' 49, z(s) = 2.012); SDSS J1322+1052 (theta = 2.'' 00, z(s) = 1.716); and SDSS J1524+4409 (theta = 1.'' 67, z(s) = 1.210, z(l) = 0.320). Each system has two lensed images. We find that the fainter image component of SDSS J0832+ 0404 is significantly redder than the brighter component, perhaps because of differential reddening by the lensing galaxy. The lens potential of SDSS J1216+ 3529 might be complicated by the presence of a secondary galaxy near the main lensing galaxy.